Which of the following is a type of polar attraction?
O
O
A. A hydrogen bond
B. An ionic bond
C. A covalent bond
D. A metallic bond
SUBMIT

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

a = executive branch; b = judicial branch

i think the answer is a.keratin is the pigment responsible for skin color.